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**1. Homework Statement**

There is a book with 2 volumes. Each volume exists in 3 different languages. Each language has 2 identical copies(total of 12 books).

In how many ways we can arrange them on a shelf, with no restrictions and order of the volumes is irrelevant?

**2. Homework Equations**

**3. The Attempt at a Solution**

I thought that since we have 12 books, we can arrange them in ##\frac{12!}{(2!)^6}## but apparently it is not correct. The correct answer is ##\frac{12!}{6!}## but I am not sure why.

What am I missing?

Thank you.

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